Spring urged fastener for location in an open rail section

ABSTRACT

A spring-biassed nut includes a generally rectangular nut body which has a spring device fitted on one main surface thereof. The nut can be fitted into a slotted hollow rail by inserting the nut through the rail slot in the direction of its plane. The spring tightens the nut against the rail legs defining the rail slot, so that the nut will be held in a chosen position along the rail by friction. A pivot point around which the long-edge flange of the nut pivots when the nut is first inserted into the rail is defined in the interior of the rail, preferably in the inner corner region between the rail side-wall and the flange. The length of the nut as measured between the edges of the long-edge flanges is essentially equal to or slightly smaller than the distance between the pivot point and the edge of the opposing rail flange. The spring device has springs which are compressed as the nut is rotated into the rail and which are partially relieved of their load after the nut has been rotated into the rail, so as to force the nut to take a slot centered position.

The present invention relates to a spring-biassed nut arrangement inwhich a nut is fitted with a spring and which is intended for movementalong and within a slotted hollow profiled rail.

BACKGROUND OF THE INVENTION

A spring fitted to a nut functions to press the nut against an innersurface of the two mutually opposing rail flanges that define a slot inthe rail, so that as a result of contact between the nut and theflanges, the nut will remain in a position to which it is set along therail. A screw can be inserted through the slot and screwed into a nutexposed in the slot.

In the simplest case, the spring-biassed nut is fitted by inserting thenut from one end of the rail. It is desirable, however, to be able tofit the nut generally radially into the rail through the slot at anychosen position therealong. The nut shall be held against rotation inthe rail and in order to be on the safe side, it is necessary to avoidnut constructions which include movable parts by means of which the nutis fitted to the rail.

DESCRIPTION OF THE BACKGROUND ART

DE-C-2,635,439 and SE-B-427,211 describe spring-biassed nuts of thedesired kind which lack mutually movable parts for insertion of the nutin the rail and which prevent the nut from rotating when fitted.

The rails concerned can be combined to form an apparatus support standor frame structure, apparatus cabinet, cable holder or the like, andbecause the nuts can be displaced along the rails a great deal offreedom is provided with regard to positioning of the screws by means ofwhich the apparatus, the cabinet or the like is secured to the rails ofsaid structure.

The type of spring-biassed nut arrangement disclosed in DE-C-2,635,439and SE-B-427,211, however, is unsatisfactory in operation, particularlywith regard to its fitting to the rail. For instance, the task offitting the nut manually to the rail is difficult to achieve, since itis first necessary to heavily compress the spring of the known nut andthen to insert the nut, with the spring compressed, in through the slotin the rail while holding the nut in a position which deviates from thefitted position of the nut by 90°. This nut arrangement requiresprimarily a rail having a depth which is greater than the length of thenut in its insertion direction, and the spring is relieved of itscompressive load immediately it has passed through the slot in the rail,therewith allowing the spring to expand. Since it is necessary to turnthe nut through an angle of 90° after having inserted the nut throughthe slot, the process of fitting the nut can become extremely difficultat times. For instance, there is the risk that the nut will beunintentionally turned through 90° in the "wrong" direction, so that thenut faces towards the bottom wall of the rail while the spring faces theslot. Naturally, there is also the risk of the nut spring supportingagainst the bottom-wall region of the slot in a decentred position. Afurther drawback with this known type of spring-biassed nut arrangementis that it is very difficult to remove the nut from the rail radiallythrough the slot.

Because the spring-biassed nut requires a large amount of free spacewithin the hollow rail, the rail is relatively large in relation to thenut and is given a depth which is at least equal to the internal widthof the rail. This results in mechanical strength problems and leads to arelatively high consumption of material in the manufacture of the rail,and also creates geometrical problems with regard to extruded profiledelements of generally rectangular cross-section, in which each elementside defines two mutually opposing flanges and an intermediate slot in ahollow profiled rail for spring-biassed nuts of the aforedescribed kind.

Accordingly, one object of the present invention is to provide aspring-biassed nut which can be easily fitted manually into anassociated slotted rail and which enables the relative depth of the railto be limited.

Further objects of the invention are stated directly or indirectlyherein, or will be realized by the person skilled in this art.

The object of the invention is achieved with a fastening apparatusincluding a body member having a pair of opposing substantially parallelside members. Each of the side members includes an outwardly extendingflange. An annular conically tapering member is attached to the bodymember and extends therefrom. The annular conically tapering member islocated approximately equidistant between the side members. A leafspring is attached to the annular conically tapering member. The leafspring has a pair of spaced-apart substantially mirror-image springmembers extending substantially parallel to the side members. The leafspring includes an aperture located approximately equidistant betweenthe spring members. The annular conically tapering member may be locatedwithin the aperture. The annular conically tapering member may include athreaded hole located therein.

The body member further includes a pair of opposing substantiallyparallel end members. Each of the end members extends substantiallyperpendicular to the side members. The end members each include astiffening element extending upwardly from the body member in adirection away from the annular conically tapering member. Thestiffening elements have a length extending between opposed endportions. The outwardly extending flanges extend beyond the end portionsof the stiffening elements. The outwardly extending flanges may betapered upwardly and outwardly.

The body member is locatable within a longitudinally extending elongatedhollow rail. The hollow rail includes a bottom wall, a pair of opposingside walls, a pair of spaced-apart upper leg portions, and a slotlocated between the spaced-apart upper leg portions. The tapered flangesof the body member may engage correspondingly tapered inner surfaces ofthe upper leg portions of the hollow rail when the body member islocated within the hollow rail. The body member is insertable into thehollow rail through the slot by a pivoting motion of the body memberabout one of the flanges.

In one embodiment of the hollow rail, the pair of opposing side wallsare inclined outwardly proceeding in a direction from the bottom wall tothe upper leg portions. The body member is locatable within this hollowrail such that the spring members engage the opposing side walls tocenter the body member within the hollow rail.

In another embodiment of the hollow rail, the bottom wall includes acentral projection extending in a longitudinal direction of the hollowrail. The body member is locatable within this hollow rail such that thespring members engage the central projection to center the body memberwithin the hollow rail.

In still another embodiment of the hollow rail, four of the hollow railsare incorporated into a generally rectangular member such that bottomwalls of the hollow rails form a central core of the generallyrectangular member, with the leg portions of the hollow rails facingoutward.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference toexemplifying embodiments thereof and also with reference to theaccompanying drawings, in which

FIG. 1 illustrates schematically an inventive spring-biassed nut fromabove;

FIG. 2 is a side view of the nut shown in FIG. 1, taken on the lineII--II of FIG. 1;

FIG. 3 illustrates schematically fitting of the inventive nut into ahollow rail;

FIG. 4 is a schematic cross-sectional view of a profiled elementcomprising four mutually identical hollow rails of the kind indicated inFIG. 3;

FIG. 5 illustrates schematically fitting of the inventive nut into ahollow rail; and

FIG. 6 illustrates schematically a variant of the nut and its hollowrail in a view corresponding to the view of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-3 illustrate a preferred embodiment of the inventivespring-biassed nut, which is intended for coaction with a hollowprofiled rail which preferably has the cross-sectional shape indicatedin FIG. 3.

The nut 1 includes a rectangular, approximately square body 10 formedfrom a sheetmetal blank in whose centre there is punched a deep-drawnhole. The blank also includes two mutually opposing long-edge elements 3which are bent-up through an angle of 90° to form a stiffening element.The body 10 thus includes a generally flat circumferential region whichmerges with a cylindrical part which includes the internal screw-thread20 of the nut body, via an annular conically tapering part 21.

A generally C-shaped spring element 5 has essentially the same length asthe body 10. Provided centrally in the web 53 of the C-shaped element 5is an opening which encircles the outer side 121 of the screw-threadedbody part and which is fixed thereto, for instance press-fitted thereto.

As shown in FIG. 3, the length of respective long-edge elements 3corresponds essentially to the free distance between the mutuallyopposing legs of the rail, i.e. corresponds to the width of the slot inthe rail 60. It will also be seen that each long-edge element 3 hasstepped height portions 31, 33 and a centre part 34, so as to besubjected to essentially the same bending or flexural strain along thewhole of its length. The body 10 includes wedge-shaped flanges 4 whoseupper surfaces 41 are angled upwardly through about 10° from the mainsurface of said body.

The legs 64 of the rail 60 have an inner surface 66 which slopescorrespondingly through an angle of about 10° to the plane defined bythe outer surfaces of the legs, so that the upper flange surfaces 41 andthe inner leg surfaces 66 will be in flat engagement with one another.Thus, if the nut 1 is subjected to a force tending to pull the nut outof the rail, the legs are able to flex outwardly to some extent in theabsence of slip between the flanges and the legs in the main plane ofthe nut surface.

In FIG. 2, the line 23 illustrates the transition between the generallyflat part of the nut body and the conical part thereof, the outersurface of said conical part being referenced 120. The circle 22represents the transition or junction between the upper flat surface 11of the nut body and the conical inner surface of the conical part. Theouter surface of the generally cylindrical deep-drawn part is referenced121.

As will be seen from FIG. 3, the spring 5 urges the spring-biassed nut 1upwardly into contact with the legs 64 of the rail, so as to hold thenut 1 in a desired position along the rail 60. It will also be seen thatlegs 51, 52 of the spring 5 support against side-wall regions of therail 60, thus providing a nut centering function which centres the nutin relation to the centre of the groove. Although it will be evidentfrom FIG. 3 that the nut is held centered because the outer corners ofthe legs 64 engage in corresponding angled recesses between theend-walls 32 of the long-edge elements 3 and the nut flanges 4, thecentering function of the spring 5 has particular significance withregard to fitting the nut in the rail 60.

FIG. 5 illustrates a stage in which one flange part A of the nut 1 hasbeen inserted into the inner corner region 71 between the legs 64 andthe side-wall 62 while compressing one leg 51 of the spring in a generaldirection which lies in the plane of FIG. 5 and which is parallel withthe upper flat surface 11 of the nut body 10.

The end-part A of the nut body 10 is in contact with the wall 62 in aregion referenced LP. The width of the nut between the tips of theflanges 4 is slightly smaller than the distance between the point LP andthe corner point SP on the legs 64. It will be seen that when theend-part A is inserted as far as possible into the inner corner region71, the nut 1 is able to swing around the point LP, so that the movableflange 4 is able to pass the opposite point SP with a small clearancethereto, wherein this swinging movement, generally indicated by thearrow Z, is counteracted by compression of the spring leg 51. When theflange 4 has passed beyond the point SP, the reaction force FR exertedby the spring leg 51 will displace the nut 1 so that the flange 4, whichwas earlier free, is driven in beneath the leg 64 at the region B andgrips the leg 64. As a result of the effect exerted by the uppersurfaces 41 and the inner surfaces 66, there is obtained an automatic,centering wedge action, due to the force exerted axially by the spring5.

It will be seen that the rail 60 has a free cross-section which tapersconically from its upper slotted part 65 in a direction towards the slotbottom region 63 against which the spring 5 acts.

An important feature of the inventive arrangement is that the nut isconstructed for insertion of one end region A inwardly of one leg 64 ofthe rail 60 and for subsequent rotation of the nut against the action ofa laterally acting spring element, so that the chosen length of the nutwill allow the opposing flange part of the nut to just pass the oppositeleg of the rail, whereafter the force exerted by the compressed springis employed to displace the nut until its earlier free flange gripsbeneath the adjacent leg.

Schematically illustrated in FIG. 5 is a force vector F which can beassumed to be exerted by the operator with a finger of one hand, whereinthe force F can be divided into a force component F2 which actsgenerally in the axial direction 70 of the nut, and a force component F1which results in an oppositely acting reaction force FR, as describedabove.

The person skilled in this art will perceive that the nut can be easilyremoved from the rail 60, for instance by inserting a screwdriver intothe screw-threaded hole of the nut, so as to press down the nut 1 andforcing one edge-region A into the inner corner 71, as illustrated inFIG. 5, and then twisting the nut up around the pivot point LP with theaid of the screwdriver.

As shown in FIG. 4, the inventive spring-biassed nut enables the rail 60to be tapered conically down towards its bottom part. Consequently,rails 60 can advantageously be combined to form an element 6 whichincludes four mutually identical rails 60, wherein the element 6 has acentral, generally rectangular part 68 in which a penetratingcylindrical passageway 69 can be provided, for instance, so as to enableseveral such elements 6 to be joined together or to facilitate mountingof the element 6 on a supportive surface.

One feature of the invention is that in addition to its conventionalfunction, the spring arrangement has a laterally acting spring functionwhich presses the nut against the inner surface of respective railflanges.

Another feature of the invention is that the rail is configured so as toform preferably in its upper part a pivoting point for one flange of thenut when the nut body extends through the rail slot and the springarrangement is located within the rail. Another feature is that thelength of the nut body is adapted so that as the nut swings around thispivot point, the other flange of said nut will just pass the adjacentleg of the rail while compressing the spring device on the opposite sidethereof, so that said spring device will drive the nut towards a slotcentered position as soon as the other flange has passed the rail leg.

Although it has been indicated above that the nut pivoting point lies onthe tip of the nut flange 4, it will be seen from FIG. 5 that the actualpoint about which the nut swings may be formed at least temporarily bythe contact point between the long edge elements 3 and the rail legs 64,or the contact point between the side-walls 62 and the underside 42 ofthe flange. In this regard, it is important that the length of the nutis so chosen that the free end of the nut will just swing past theadjacent legs 64 and that a nut pivoting region is found, for example inthe rail angle between leg and side-wall.

Although the hollow space defined by the profiled rail has been shown tohave a generally trapezoidal cross-sectional shape by way of example, itwill be understood that other cross-sectional shapes are possible, forinstance, a generally rectangular shape. Furthermore, the spring-biassednut has been shown to coact with a side-wall of the hollow rail, on thebasis that the rail has an upper slotted wall, a bottom wall and twoside-walls. It will be understood, however, that the bottom wall mayalternatively have a raised portion or a sunken portion and that the nutspring can be arranged to coact with the side-walls of said portions ina manner to centre the nut in the slot. In this case, the nut spring isprovided with spring means capable of coacting with both sides of therecessed portion or raised portion. The spring shall also supportagainst upwardly turned surfaces in the hollow rail so as to tension thenut upwardly into stable frictional contact with downwardly facing railsurfaces. The internal width of the hollow rail between the sidesurfaces thereof will preferably be greater than the height between thebottom wall and the legs of the rail. The hollow space contained by therail and the spring nut will preferably have a cross-sectional shapewhich is symmetrical in relation to a centre plane between the rail legsand the nut flanges respectively.

The variant illustrated in FIG. 6 corresponds to the variant illustratedin FIG. 5 with the following exceptions. The bottom region of theprofiled hollow rail includes a central, longitudinally extendingelevation 160 which forms a guide strip. The nut has spring legs 51, 52which are formed for coaction with the sides 162 of the elevation 160,so that at least one of the nut spring legs will support against oneside 162 and be compressed thereby as the nut is swung in through theslot, and then move the nut to a central position in relation to theslot, at the same time as the spring legs 51, 52 press the nut againstthe rail legs 64. In the case of the FIG. 6 embodiment, thespring-biassed nut device has the form of a rectangular sheetmetalelement and the nut body extends through a centre region of saidelement. Two mutually opposing edge-parts of the element are bentthrough an angle of about 270°, for instance, to form the spring legs51, 52, and are intended to receive and contact the elevation 160therebetween.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

We claim:
 1. A fastening apparatus comprising:a body member having apair of opposing substantially parallel side members, each of said sidemembers including an outwardly extending flange; an annular conicallytapering member attached to said body member and extending therefrom,said annular conically tapering member being located approximatelyequidistant between said side members; and a leaf spring attached tosaid annular conically tapering member, said leaf spring having a pairof spaced-apart substantially mirror-image spring members extendingsubstantially parallel to said side members.
 2. The fastening apparatusaccording to claim 1, wherein said leaf spring includes an aperturelocated approximately equidistant between said spring members, saidannular conically tapering member being located within said aperture. 3.The fastening apparatus according to claim 2, wherein said annularconically tapering member includes a threaded hole located therein. 4.The fastening apparatus according to claim 3, wherein said body memberfurther includes a pair of opposing substantially parallel end members,each of said end members extending substantially perpendicular to saidside members.
 5. The fastening apparatus according to claim 4, whereinsaid end members each include a stiffening element extending upwardlyfrom said body member in a direction away from said annular conicallytapering member.
 6. The fastening apparatus according to claim 5,wherein said stiffening elements have a length extending between opposedend portions, and wherein said outwardly extending flanges extend beyondsaid end portions of said stiffening elements.
 7. The fasteningapparatus according to claim 1, wherein said annular conically taperingmember includes a threaded aperture located therein.
 8. The fasteningapparatus according to claim 7, wherein said body member furtherincludes a pair of opposing substantially parallel end members, each ofsaid end members extending substantially perpendicular to said sidemembers.
 9. The fastening apparatus according to claim 8, wherein saidend members each include a stiffening element extending upwardly fromsaid body member in a direction away from said annular conicallytapering member.
 10. The fastening apparatus according to claim 9,wherein said stiffening elements have a length extending between opposedend portions, and wherein said outwardly extending flanges extend beyondsaid end portions of said stiffening elements.
 11. The fasteningapparatus according to claim 1, wherein said body member furtherincludes a pair of opposing substantially parallel end members, each ofsaid end members extending substantially perpendicular to said sidemembers.
 12. The fastening apparatus according to claim 11 wherein saidend members each include a stiffening element extending upwardly fromsaid body member in a direction away from said annular conicallytapering member.
 13. The fastening apparatus according to claim 12,wherein said stiffening elements have a length extending between opposedend portions, and wherein said outwardly extending flanges extend beyondsaid end portions of said stiffening elements.
 14. The fasteningapparatus according to claim 1, and further comprising a longitudinallyextending elongated hollow rail, said hollow rail including a bottomwall, a pair of opposing side walls, a pair of spaced-apart upper legportions, and a slot located between said spaced-apart upper legportions.
 15. The fastening apparatus according to claim 14, whereinsaid pair of opposing side walls are inclined outwardly proceeding in adirection from said bottom wall to said upper leg portions, and whereinsaid body member is locatable within said hollow rail such that saidspring members engage said opposing side walls to center said bodymember within said hollow rail.
 16. The fastening apparatus according toclaim 15, wherein said leaf spring includes an aperture locatedapproximately equidistant between said spring members, said annularconically tapering member being located within said aperture,saidannular conically tapering member includes a threaded hole locatedtherein; said body member further includes a pair of opposingsubstantially parallel end members, each of said end members extendingsubstantially perpendicular to said side members; said end members eachinclude a stiffening element extending upwardly from said body member ina direction away from said annular conically tapering member; saidstiffening elements have a length extending between opposed endportions; said outwardly extending flanges extend beyond said endportions of said stiffening elements; said outwardly extending flangesare tapered upwardly and outwardly; said flanges engage correspondinglytapered inner surfaces of said upper leg portions when said body memberis located within said hollow rail; and said body member is insertableinto said hollow rail through said slot by a pivoting motion of saidbody member about one of said flanges.
 17. The fastening apparatusaccording to claim 14, wherein said bottom wall includes a centralprojection extending in a longitudinal direction of said hollow rail,and wherein said body member is locatable within said hollow rail suchthat said spring members engage said central projection to center saidbody member within said hollow rail.
 18. The fastening apparatusaccording to claim 17, wherein said leaf spring includes an aperturelocated approximately equidistant between said spring members, saidannular conically tapering member being located within saidaperture;said annular conically tapering member includes a threaded holelocated therein; said body member further includes a pair of opposingsubstantially parallel end members, each of said end members extendingsubstantially perpendicular to said side members; said end members eachinclude a stiffening element extending upwardly from said body member ina direction away from said annular conically tapering member; saidstiffening elements have a length extending between opposed endportions; said outwardly extending flanges extend beyond said endportions of said stiffening elements; said outwardly extending flangesare tapered upwardly and outwardly; said flanges engage correspondinglytapered inner surfaces of said upper leg portions when said body memberis located within said hollow rail; and said body member is insertableinto said hollow rail through said slot by a pivoting motion of saidbody member about one of said flanges.
 19. The fastening apparatusaccording to claim 14, wherein said outwardly extending flanges aretapered upwardly and outwardly, and wherein said flanges engagecorrespondingly tapered inner surfaces of said upper leg portions whensaid body member is located within said hollow rail.
 20. The fasteningapparatus according to claim 14, wherein four of said hollow rails areincorporated into a generally rectangular member such that bottom wallsof said hollow rails form a central core of said generally rectangularmember with said leg portions of said hollow rails facing outward.